Vehicle tyre

Abstract

Vehicle tyre with a tread (1) designed in a directional manner and having a profile designed mirror-symmetrically to the central circumferential line (AA) of the tread (1) with two shoulder-side block rows (2) and further block rows (3, 4) arranged between these, separated from one another by circumferential grooves (5), wherein transverse grooves (6) are provided which each run approximately according to a single wavelength of a sinusoidal wave with a single wave crest on the central circumferential line (AA).The tread (1) has a central block row (4) running along the center circumferential line (AA) of the tread (1) and a middle block row (3) between this and the shoulder-side block rows (2), wherein the central block row (4) has a largest width (B4) projected in the axial direction of 10% to 15% of the width (B) of the tread (1) and the shoulder-side block rows (2) have the largest width (B2) of all block rows (2, 3, 4).

Description

[0001] The invention relates to a vehicle tire with a tread designed in a directional manner with a profile designed mirror-symmetrically or approximately mirror-symmetrically to the center circumferential line of the tread with two shoulder-side rows of blocks and further rows of blocks arranged between these, separated from one another by circumferential grooves, wherein all rows of blocks are divided into profile blocks by the circumferential grooves and by transverse grooves running continuously and parallel to one another across the width of the tread in the ground contact area, wherein the transverse grooves each run approximately according to a single wavelength of a sinusoidal wave with a single wave crest at the center circumferential line.

[0002] Such a vehicle tire is known, for example, from DE 10 2018 218 252 A1. The tread of the vehicle tire has a profile consisting of two shoulder-side block rows and two further block rows running between them, which are separated from one another by a circumferential groove running straight in the circumferential direction along the central center circumferential line. The block rows are divided into tread blocks by transverse grooves running parallel to one another, which are provided with depressions adjacent to the transverse grooves and open towards the tread periphery. The transverse groove sections in the block rows are each composed of two subsections which enclose an obtuse angle with one another and adjoin one another at a bend with an outer bend side and an inner bend side, wherein the depressions are formed in the region of the outer bend side of the bend points.A tread designed in this way is intended to ensure effective interlocking of the snow accumulating in the transverse grooves in the area of the depressions, so that a good snow grip of a tire with such a tread is ensured, whereby in wet conditions water is to be diverted in a low-turbulence manner over the bends to a circumferential groove.

[0003] The invention is based on the object of improving a tread of the type mentioned at the outset with regard to the response to steering forces and the handling properties on snow-covered and dry surfaces while maintaining winter performance, in particular good snow grip properties and good water drainage capacity.

[0004] The stated object is achieved according to the invention in that the tread has a central block row running along the center circumferential line of the tread and a middle block row between this and the shoulder-side block rows, wherein the central block row has a width projected in the axial direction of 12% to 16% of the width of the tread and the shoulder-side block rows have the greatest width of all block rows.

[0005] Instead of a wide circumferential groove, the tread according to the invention therefore has a relatively wide central row of blocks, which advantageously stiffens the tread in the central region, and the widest rows of blocks at the tire shoulders, whereby the response of the tire to steering forces is noticeably improved and thus the handling characteristics are also improved, in particular on snowy but also on dry surfaces.

[0006] In a preferred design, the shoulder-side block rows have a maximum projected width of 23% to 30% of the tread width in the axial direction, and the center block rows have a maximum projected width of 15% to 18% of the tread width in the axial direction. The further the block rows are positioned toward the outside of the tread, the greater their width or the width of their tread blocks. This measure allows for particularly balanced handling characteristics.

[0007] Good grip properties on snow and wet surfaces are further supported by the fact that all groove sections of the transverse grooves running between the tread blocks are straight, with the center lines of the groove sections in the shoulder-side block rows each forming an angle of 75° to 85° with the circumferential direction and the center lines of the groove sections of the transverse grooves in the middle block rows each forming an angle of 55° to 65° with the circumferential direction.

[0008] According to a further preferred embodiment, the groove sections in the central block row are each composed of two straight sections symmetrically to the center circumferential line, which adjoin one another at the center circumferential line in a flat V-shape and have center lines that, inclined in opposite directions, each enclose an angle of 70° to 80° with the circumferential direction of the tread. These groove sections contribute to water drainage from the center of the tread and, on the other hand, are advantageous for low rolling noise, particularly due to their flat V-shaped arrangement.

[0009] For particularly effective water drainage on wet surfaces, it is also advantageous if the groove sections in the central block row have a constant width of 4.00 mm to 5.00 mm, measured between their edge margins on the tread periphery. This width is smaller than the width of the groove sections of the transverse grooves in the middle and shoulder-side block rows. The width of the groove sections of the transverse grooves therefore increases from the tread center to the tire shoulders, which particularly favorably supports water drainage to the tread outer edges.

[0010] The circumferential grooves also contribute to good water drainage and, at the same time, to good grip on snow. They each have a constant width of 4.50 mm to 10.00 mm, determined between their edge margins on the tread periphery. Within the sections running between adjacent tread blocks, they are composed of two long sections oriented at an angle of 2° to 5° to the circumferential direction and a short section connecting these sections, which runs at an angle of 25° to 35° to the circumferential direction. All of the sections are designed in such a way that an uninterrupted view through the circumferential grooves, a so-called "look-through", is possible over the circumference of the tread.

[0011] Further features, advantages and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates an embodiment. The sole drawing figure shows,

[0012] Fig. 1 , a plan view of a section of a circumferential section (as a development in the plane) of a tread of a vehicle tire with an embodiment variant of the invention.

[0013] Vehicle tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, preferably for passenger cars (PCs), vans (transporters) or SUVs, and preferably pneumatic vehicle tires, particularly preferably pneumatic vehicle tires of radial design for rims with an integer rim diameter of 13 inches to 24 inches, in particular of 18 inches to 23 inches, wherein the tires are intended for driving under winter driving conditions as winter tires or all-season tires.

[0014] Fig. 1 shows a section of a circumferential section of a tread which is provided with a directional tread pattern, so that a vehicle tire with such a tread can be mounted in a specific rolling direction when driving forward. Fig. 1The arrow R drawn on the left edge of the tread symbolizes the rolling direction when driving forward. Line AA marks the equatorial plane and thus the central circumferential line of tread 1, whose profile is mirror-symmetrical or approximately mirror-symmetrical with respect to this line. The ground contact area of the tread corresponds to the statically determined footprint (determined with a tire mounted on a standard rim, loaded at 70% of the maximum load capacity, internal pressure 85% of the standard pressure, according to ETRTO standards) and has a maximum width B in the axial direction, with the lateral tread edges designated L.

[0015] The tread pattern 1, which is considered within the width B in the description and claims, is comprised of two shoulder-side block rows 2, a central block row 4 running along the center circumferential line AA, and, in each tread half, a central block row 3 arranged between the shoulder-side block row 2 and the central block row 4. The block rows 2, 3, and 4 are separated from one another by circumferential grooves 5 which, apart from locations where tread wear indicators may be formed, are designed to the maximum tread depth provided for in each case, which for the preferred tire types mentioned above is in the range of 6.00 mm to 11.00 mm.

[0016] Transverse grooves 6, which run parallel to one another in the circumferential direction of the tread 1 and are symmetrical to the center circumferential line AA, together with the aforementioned circumferential grooves 5, divide the shoulder-side block rows 2 into tread blocks 2a, the middle block rows 3 into tread blocks 3a, and the central block row 4 into tread blocks 4a. The transverse grooves 6 run across the width B approximately according to a single wavelength of a sinusoidal wave with a single wave crest at the center circumferential line AA and with groove sections 6a in the shoulder-side block rows 2, groove sections 6b in the middle block rows 3, and groove sections 6c in the central block row 4. The groove sections 6a each run straight; their center lines m 6a each enclose an angle α with the circumferential direction, which angle α is the same in all groove sections 6a and is between 75° and 85°.The groove sections 6b of the transverse grooves 6 in the middle block rows 3, which also run straight, have center lines m 6b, each of which runs at an angle β of 55° to 65° to the circumferential direction. The groove sections 6c in the central block row 4 are each composed symmetrically to the center circumferential line AA of two straight partial sections 6c 1 and 6c 2, which adjoin one another at the line AA, run in a flat V-shape to one another and have center lines m 6c1, m 6c2, which, inclined in opposite directions to one another, each enclose an angle γ with the circumferential direction of the tread, which angle is 70° to 80° and is in particular 10° to 20° greater than the angle β.

[0017] The groove sections 6a, 6b, and 6c each have a constant or nearly constant width b 6a (groove sections 6a), b 6b (groove sections 6b), and b 6c (groove sections 6c or 6c 1 and 6c 2 ), wherein the widths b 6a , b 6b , and b 6c are determined between the edge portions of the groove sections 6a, 6b, and 6c present at the tread periphery. The width b 6a of the groove sections 6a is 4.00 mm to 8.00 mm, and the width b 6b of the groove sections 6b is 3.00 mm to 6.00 mm. In the embodiment shown, the groove sections 6a are designed such that their width b 6a is greatest at the tread edges l, wherein the width b 6a of the groove sections 6a up to their junction areas into the adjacent circumferential grooves 5 is 2% to 5% smaller than their width at the widest point mentioned.The groove sections 6b have their greatest width b 6b at their junction areas with the circumferential groove 5 located further outside the tread. The width b 6b decreases continuously toward the junction areas with the circumferential groove 5 located further inside the tread, where it amounts to 80% to 90% of the greatest width. The width b 6c of the groove sections 6c or their subsections 6c 1 and 6c 2 is constant and amounts to 3.00 mm to 4.00 mm.

[0018] The groove sections 6c of the transverse grooves 6 in the central block row 4 and the groove sections 6b of the transverse grooves 6 in the middle block rows 3 preferably have corresponding depths, which are each constant or decrease from the tread center and amount to at least 80%, in particular 90% to 100% of the tread depth. The groove sections 6a of the transverse grooves 6 in the shoulder-side block rows 2 have a depth, in particular over approximately 50% of their extension length beginning at the circumferential groove 5, which corresponds to the depth of the groove sections 6b and 6c, as described. In the direction toward the tread edges 1 and in the tire shoulders located outside these edges, the depth of the transverse grooves 6 decreases continuously in a known manner.

[0019] With regard to the width B, the shoulder-side block rows 2 or their profile blocks 2a further have a greatest width B 2 projected in the axial direction of 23% to 30% of the width B, the middle block rows 3 or their profile blocks 3a have a greatest width B 3 projected in the axial direction of 12% to 18% of the width B and the central block row 4 or its profile blocks 4a have a greatest width B 4 projected in the axial direction of 12% to 16% of the width B. The width B 2 is thus greater than the widths B 3 and B 4 , wherein the width B 3 is preferably greater than the width B 4 .

[0020] The circumferential grooves 5 each have a constant width Bu, determined between their edge edges on the tread periphery, which ranges from 4.50 mm to 10.00 mm. Furthermore, within their sections extending between adjacent tread blocks 2a-3a, 3a-4a, the circumferential grooves 5 are each composed of two long sections 5a oriented at an angle δ of 2° to 5° to the circumferential direction, and a short section 5b connecting these sections, which runs at an angle δ' of 25° to 35° to the circumferential direction. The inclination of the sections 5a, 5b is opposite to one another in the two tread halves. The design of the lengths and angles of the sections 5a, 5b is such that an uninterrupted view through the circumferential grooves 5 is possible over the circumference of the tire.

[0021] Since the preferred design of the vehicle tire is a winter tire or all-season tire, all tread blocks 2a, 3a, and 4a are each provided with a number of incisions 7, each extending parallel to one another and parallel to the transverse groove sections 6a, 6b, and 6c. Furthermore, in the illustrated design, all incisions 7 are straight incisions in plan view; in alternative designs, they are wave-shaped or zigzag-shaped. List of reference symbols

[0022] 1Tread 2Shoulder-side block row 2aTread block 3Middle block row 3aTread block 4Central block row 4aTread block 5Circumferential groove 5a, 5bSubsection 6Transverse groove 6a, 6b, 6cGroove section 6c1, 6c2Subsection 7Cut-off α, β, γ, δ, δ'Angle BWidth of the tread 1 BuWidth of the circumferential grooves B2, B3, B4 Width of the block rows b6a, b6b Width of the groove sections 6a, 6b b6c, b6c1, b6c2 Width of the groove section 6c and the subsections 6c1, 6c2 m6a, m6b Center lines of the groove sections 6a, 6b m6c1 , m 6c2 Center lines of sections 6 c1 , 6 c2 A-ACenter circumference line ILread edge RLearing direction when driving forward

Claims

1. Vehicle tire with a tread (1) designed in a directional manner and having a profile designed mirror-symmetrically or approximately mirror-symmetrically to the center circumferential line (AA) of the tread (1) with two shoulder-side block rows (2) and further block rows (3, 4) arranged between them, separated from one another by circumferential grooves (5), wherein all block rows (2, 3, 4) are divided into profile blocks (2a, 3a, 4a) by the circumferential grooves (5) and by transverse grooves (6) running continuously and parallel to one another across the width (B) of the tread (1) in the ground contact area, wherein the transverse grooves (6) each run approximately according to a single wavelength of a sinusoidal wave with a single wave crest at the center circumferential line (AA), characterized by thatthe tread (1) has a central block row (4) running along the center circumferential line (AA) of the tread (1) and a middle block row (3) between this and the shoulder-side block rows (2), wherein the central block row (4) has a greatest width (B4) projected in the axial direction of 12% to 16% of the width (B) of the tread (1) and the shoulder-side block rows (2) have the greatest width (B2) of all block rows (2, 3, 4).

2. Vehicle tyre according to claim 1, characterized in that the shoulder-side block rows (2) have a maximum width (B2) projected in the axial direction of 23% to 30% of the width (B) of the tread (1) and the middle block rows (3) have a maximum width (B3) projected in the axial direction of 12% to 18% of the width (B) of the tread (1).

3. Vehicle tyre according to claim 1 or 2, characterized in thatall groove sections (6a, 6b, 6c) of the transverse grooves (6) running between the profile blocks (2a, 3a, 4a) are straight, the center lines (m 6a ) of the groove sections (6a) in the shoulder-side block rows (2) each enclose an angle (α) with the circumferential direction, which is 75° to 85° and the center lines (m 6b ) of the groove sections (6b) of the transverse grooves (6) in the middle block rows (3) each run at an angle (β) of 55° to 65° to the circumferential direction.

4. Vehicle tyre according to one of claims 1 to 3, characterized in that the groove sections (6c) in the central block row (4) are each composed symmetrically to the central circumferential line (AA) of two straight sections (6c1, 6c2), which adjoin one another at the central circumferential line (AA) in a flat V-shape and form center lines (m 6c1 , m 6c2) which, inclined in opposite directions to each other, form an angle (γ) of 70° to 80° with the circumferential direction of the tread.

5. Vehicle tyre according to one of claims 1 to 4, characterized in that the groove sections (6c) in the central block row (4) have a constant width (b 6c ) of 4.00 mm to 5.00 mm, which is smaller than the widths (b 6a , b 6b ) of the groove sections (6a, 6b) of the transverse grooves (6) in the middle and shoulder-side block rows (2, 3).

6. Vehicle tyre according to one of claims 1 to 5, characterized in thatthe circumferential grooves (5) each have a constant width (Bu) determined between their marginal edges on the tread periphery, which is 4.50 mm to 10.00 mm, and are composed, within their sections running between adjacent profile blocks (2a - 3a, 3a - 4a), of two long partial sections (5a) oriented at an angle (δ) of 2° to 5° to the circumferential direction and a short partial section 5b connecting these, which runs at an angle (δ') of 25° to 35° to the circumferential direction, wherein the partial sections (5a, 5b) are designed in such a way that an uninterrupted view through the circumferential grooves (5) is possible over the circumference of the tread (1).

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